Google Analytics has recently announced the addition of bots and spider filtering. This was posted on Google+ by Matthew Anderson of the Google Analytics Team. This addition will make it easier to understand the real traffic that comes to your pages.
You can select a new checkbox option after going to the Admin panel and clicking on the “view settings”. This option will be labeled "Exclude traffic from known bots and spiders". All the hits from bots and spiders on the IAB ‘s International Spiders & Bots List will be excluded from user stats. The backend will exclude hits that match the User Agents named in the list as though they were subject to a profile filter. Through this you can identify the real number of visitors coming to your site.
Matthew Anderson clarified in the comments section of the Google+ post that bot filtering will be available for all versions of Google Analytics, also that the roll out should be complete by the end of Thursday.Bots and Spider Filtering Added to Google Analytics!,